Chevrolet 70 1969 Series, Shop Manual

Page: 734 / 913

ENGINE ELECTRICAL 6Y-19
F ig u re 1 5 — R e p la c in g D io d e s in E n d F ra m e
insulators which are retained in heat sink by lugs.
When installing junction studs, force insulators into
place in heat sink, then while supporting heat sink, press
studs into insulators until flange is seated at insulators.
C A U T IO N : Do nol strike studs or heat sin k if
diodes are installed, as shock m a y dam age the
diodes.
Capacitor Replacement
Capacitor is retained in end frame by a spring steel re­
tainer having both internal and external teeth.
To replace capacitor it must be removed and new one
installed by pressing on inside or “ pig tail" end as shown
in Figure 13. It is not necessary to remove heat sink to
remove capacitor.
Use shouldered diode installer (J-9600-2) or equivalent
F ig u re 1 6 — In s ta llin g D io d e s in H e a t S in k
tool for pressing operation. Do not strike or drive the
capacitor as diodes in end frame or heat sink may be
damaged by shock.
Always test capacitor after installation.
Generator Brush Replacement
With generator disassembled into major components as
covered previously under “ Generator Disassembly," the
brushes may be replaced as instructed in following steps
referring to Figure 14 for key numbers.
1. Remove the two brush holder retaining screws (7 and
8) and the brush holder (2) with strap (3) from slip
ring end frame (16). Note the position of the various
parts as shown in Figure 14.
2. Assemble brush holder (2) and new brushes (5 and 11)
to end frame. Notice that brush (11) has larger hole
in “ pig tail" terminal than brush (5). This brush
carries field current to slip ring on rotor shaft (fig.
17) and is insulated from end frame. Insulator (10)
passes through hole in terminal. Brush (5) with small
hole in terminal is ground brush and is connected to
end frame by ground screw (7). Indicator light strap
(3) is insulated from end frame and lower end must
engage diode junction stud (14) as shown.
3. Assemble brush springs (12) and brushes in brush hol­
der with brush leads fitting in respective slots in brush
holder (2). Depress brushes and insert a straight wire
or pin (15) through holes provided in brush holder
and end frame. End of pin (15) must protrude
through hole in end frame so it can be removed after
generator is assembled.
Diode Replacement
Special tools are required for replacing diodes in heat
sink and end frame.
F ig u r e 1 7 — Rotor a n d S lip R in g A s s e m b ly
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L